glossAPI/e-nautilia

Hellenic Merchant Marine Academy Textbooks - Εκπαιδευτικά Κείμενα Ακαδημιών Εμπορικού Ναυτικού

Dataset Info

This dataset is a structured digital collection of 31 educational textbooks (Εκπαιδευτικά Κείμενα) used in the Hellenic Merchant Marine Academies (Ακαδημίες Εμπορικού Ναυτικού). The textbooks cover the full curriculum of nautical and engineering studies, including physics, mathematics, applied mathematics, communications, radar, naval meteorology, ship stability, marine law, refrigeration and air-conditioning systems, electrical machines, internal combustion engines, naval electronics, fluid mechanics, cargo transport, ship economic operation, and other domains relevant to merchant marine officer training.

The dataset was sourced from the educational portal of the Hellenic Merchant Marine Academies (https://www.eef.edu.gr/) and extracted from the original PDFs. Each entry corresponds to a single textbook and includes the title, the full body of the book, and a permanent link back to the original PDF.

The texts include scientific, mathematical, legal, and technical content in Modern Greek, with extensive tabular data, formulas, indices/exponents, and structured lists.

Metadata Info

Column	Type	Description
title	string	Book title (e.g., Φυσική, Μαθηματικά, Ναυτική Μετεωρολογία, Στοιχεία Ναυτικού Δικαίου)
content	string	Full text of the textbook, with tables and mathematical formatting preserved as HTML markup (<table>, <tr>, <td>, <sup>, <sub>, <br>)
pdf_url	string	Source URL of the original PDF on www.eef.edu.gr

Dataset Statistics

• Textbooks (rows): 31
• Size: 4.61 MB
• Words: 1.140.500 (counted on title + content, whitespace-separated)
• Tokens: 2.657.504 (counted on title + content with the nlpaueb/bert-base-greek-uncased-v1 WordPiece tokenizer, no special tokens, no truncation)

Note on Content Formatting

Because these textbooks contain a high density of mathematical formulas, scientific tables, engineering diagrams, and structured technical content, the body text is preserved with HTML markup rather than being flattened to plain text. Tables are kept as <table>/<tr>/<td> structures, and superscripts/subscripts (essential for formulas, units, and exponents) are kept as <sup> and <sub>. This preserves the structural information that would otherwise be lost or misrepresented in plain text and makes the dataset more useful for downstream tasks that rely on tabular and mathematical content.

A few side effects of this approach are worth noting:

• HTML entities such as <, >, and & appear where the original content contained literal <, >, or & characters (e.g., the inequality < 10³ is rendered as &lt; 10<sup>3</sup>). This is correct HTML behavior.
• In one textbook (Πληροφορική - Ηλεκτρονικοί Υπολογιστές), some placeholder strings written in angle brackets in the source (e.g., <filename>, <password>, <paramters>) were ambiguously interpreted by the extractor as HTML tags. These reflect the source extraction faithfully and have not been silently corrected.

Usage

This dataset is useful for:

• Natural Language Processing (NLP) tasks for Modern Greek, especially in the technical, scientific, and maritime registers
• Building Greek language models or domain-adapted embeddings for STEM and nautical education
• Extraction and modeling of tabular and mathematical content in Greek
• Maritime, navigation, and marine engineering research and education
• Training downstream tools for Greek scientific Q&A, summarization, and classification

License

This dataset is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Any commercial use requires prior written permission from the publisher of the original textbooks. All intellectual property rights in the underlying books remain with their original publishers and authors. The dataset is derived from publicly accessible PDFs and is provided for non-commercial research, scholarship, and educational use.

Contact

For feedback contact: glossapi.team@eellak.gr